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<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
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  <body>
    <script>
      let x = 10;
      /* 
        let y = ++x; // 前置 ++
        ① x++; 
        ② let y = x;
      */
      let y = ++x; // 前置 ++
      console.log(y); //11
      console.log(x); //11
    </script>
  </body>
</html>
